Project Summary/Abstract Over 1 million Americans currently live with lower limb amputations and the number is expected to more than double by 2050. More than 80% of all lower limb amputations result from vascular complications due to diseases such as severe diabetes mellitus and/or severe peripheral artery disease, known as dysvascular amputation. The population of Veterans with dysvascular lower limb amputation is growing, and high levels of mortality and disability highlight the significance of identifying ways to optimize physical rehabilitation. The dysvascular amputation population is characterized by: 1) low levels of physical activity and 2) high rates of disability. Such poor physical activity and disability outcomes are likely linked to chronic physical activity behaviors that Veterans adopt before dysvascular lower limb amputation and carry over after amputation. Therefore, the primary aim of this pilot study is to determine the feasibility of using a physical-activity behavior-change (PABC) intervention for increasing physical activity and reducing disability in Veterans 1-5 years following dysvascular lower-limb amputation. This pilot study will be the first to assess the feasibility of using a PABC intervention for older adult Veterans with dysvascular amputation. The PABC intervention is three months in duration. Testing will occur at baseline (pre-intervention), three months (end of intervention), and six months. Feasibility will be determined using measures of 1) participant retention, 2) dose goal attainment, 3) participant acceptability, 4) safety, and 5) initial effect size. Effect size will be based on the outcome measures of accelerometer-based physical activity and self-report disability using the Late-Life Function and Disability Index. This pilot study addresses an understudied and growing population of older Veterans characterized by complex health conditions. The outcome will significantly advance current research by providing critical feasibility data related to improving the chronic low physical activity and high levels of disability experienced by this population of older Veterans.